Accretion onto Planetary Mass Companions of Low-Mass Young Stars

Measurements of accretion rates onto planetary mass objects may distinguish between different planet formation mechanisms, which predict different accretion histories. In this Letter, we use \HST/WFC3 UVIS optical photometry to measure accretion rates onto three accreting objects, GSC06214-00210 b, GQ Lup b, and DH Tau b, that are at the planet/brown dwarf boundary and are companions to solar mass stars.

The excess optical emission in the excess accretion continuum yields mass accretion rates of 10 9 to 10 11 \Msol/yr for these three objects. Their accretion rates are an order of magnitude higher than expected from the correlation between mass and accretion rates measured from the UV excess, which is applicable if these wide planetary mass companions formed by protostellar core fragmentation. The high accretion rates and large separation from the central star demonstrate the presence of massive disks around these objects. Models for the formation and evolution of wide planetary mass companions should account for their large accretion rates. High ratios of H

luminosity over accretion luminosity for objects with low accretion rates suggest that searches for H emission may be an efficient way to find accreting planets.

Yifan Zhou, Gregory J. Herczeg, Adam L. Kraus, Stanimir Metchev, Kelle Cruz (Submitted on 25 Jan 2014)

Comments: 7 pages, 5 figures, 2 tables Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Cite as: arXiv:1401.6545 [astro-ph.SR] (or arXiv:1401.6545v1 [astro-ph.SR] for this version)

Submission history From: Yifan Zhou [v1] Sat, 25 Jan 2014 15:23:40 GMT (2026kb) 

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